Automatic feed mechanism for a gun



June 20, 1967 B. MAILLARD AUTOMATIC FEED MECHANISM FOR A GUN Filed Feb. 23, 1965 2 Sheets-Sheet 1 3% m MN June 20, 1967 Filed Feb. 23, 1965 B. MAILLARD AUTOMATIC FEED MECHANISM FOR A GUN 2 Sheets-Sheet 2 United States Patent AUTOMATIC FEED MECHANISM FOR A GUN Bernard Maillard, Geneva, Switzerland, assignor t0 Brevets Aero-Mecaniques S.A., Geneva, Switzerland, a society of Switzerland Filed Feb. 23, 1965, Ser. No. 434,572 Claims priority, application Luxembourg, Feb. 25, 1964, 45,519 3 Claims. (Cl. 89-33) The present invention relates to guns, and in particular automatic guns, of a caliber ranging preferably from 20 to 50 mm. and to which ammunition is fed through a mechanism automatically actuated by the gun itself.

The invention is more especially, but not exclusively, concerned with guns where the ammunition is carried by a belt actuated by a belt feed mechanism.

The chief object of the present invention is to provide a gun of this type which is better adapted than those existing up to the present time to meet the requirements of practice, in particular concerning the safety of operation of the feed mechanism.

The invention is concerned with guns including a movable breechblock having a reciprocating movement, and a feed device actuated by energy supplied along an energy transmission path from a resilient energy accumulator periodically receiving energy from a movable portion of the gun other than the breechblock thereof but having a reciprocating movement in synchronism with that of said breechblock, which movable portion may be the whole of the gun when the latter is mounted to recoil, against the action of a buffer system, on a stationary cradle supporting the gun feed device.

According to an essential feature of the present invention, the movable breechblock of the gun is operatively connected in a permanent and continuous fashion with the movable parts of the feed mechanism to be actuated, this connection being effected through a positive transmission mechanism capable of positively piloting said movable parts in respect to the movements of said breechblock, that is to say through a transmission mechanism capable of constantly controlling the instantaneous positions of said movable parts in accordance with the instantaneous position of the movable breechblock of the gun.

A preferred embodiment of the present invention will be hereinafter described with reference to the appended drawing given merely by way of example, and in which:

FIG. 1 is a diagrammatic longitudinal view illustrating the operation of the feed mechanism of a movable breechblock automatic gun;

FIG. 2 is an end view of some parts illustrated by the diagram of FIG. 1, certain of said parts being shown in a position rotated at 90 about an axis perpendicular to the plane of the drawings, for the sake of clarity;

FIG. 3 is a diagram illustrating the operation of the gun,

Automatic gun I is adapted to recoil with respect to a cradle 200, with the interposition between them of a buffer spring 201. Gun 1 having a gun barrel rigidly attached thereto comprises a breechblock 34 having a reciprocating longitudinal movement. The ammunition feed device, carried by cradle 200, is adapted to be actuated automatically by the gun.

Said feed mechanism comprises a sliding member 143 having a reciprocating transverse movement and provided with pawls 143 adapted to catch the ammunition belt and to move it forward one step for every active stroke of said sliding member 143. The strokes of sliding member 143 in the opposed direction produce no displacement of the ammunition belt.

In a known manner, the main driving force causing active strokes of sliding member 143 is produced by a resilient energy accumulator carried by cradle 200 and periodically energized, at the rate of firing, by the recoil of gun 1 with respect to its cradle 200.

According to the present invention the sliding member 143 of the feed mechanism is operatively connected with the breechblock 34 of the gun through positive transmission means capable of ensuring a piloting or regulation of the movement of sliding member 143 in response to movement of breechblock 34, that is to say a transmission mechanism such that to every position of breechblock 34 there corresponds a well determined position of sliding member 143.

In other words, owing to such positive transmission means and during the whole of the cycle of operation of the gun, the instantaneous position of sliding member 143 is constantly determined by the instantaneous position of breechblock 34 according to a predetermined law depending upon the characteristics of said transmission mechanism.

It will be understood that it is therefore possible, owing to a suitable arrangement of said mechanism, to obtain the desired law of movement for sliding member 143, this result being obtained without imposing important supplementary stresses to breechblock 34 such as would take place if the energy necessary for ensuring the active strokes of said sliding member 143 were supplied by said breechblock instead of being supplied, as it is the case with the present invention, by a resilient energy accumulator stressed, on every shot that is fired, by the recoil of gun I with respect to its cradle 200.

The resilient energy accumulator is made as follows:

There is provided, on the side of sliding member 143, a transverse fork 143,, subjected to the action of a compression spring 202 urging said sliding member 143 in the direction of its active strokes. Said spring 202 bears at one end upon an abutment 203 with trunnions 204 engaged in notches formed in the arms of said fork 143 The other end of spring 202 bears against an abutment 205 slidable upon a rod 207 rigid with abutment 203 and acting as guide for said spring 202.

In order periodically to stress spring 202 at the rate of firing, use is made of an oscillating lever 208 pivoting about a pin 2'09 rigid with the gun cradle 200. One of the arms of this lever 208 is in the form of a fork bearing against trunnions 206 carried by sliding abutment 205. The other end of said lever 208 carries, journalled thereto, a roller 210 opposite which there is provided a roller 211 journalled about an axis fixed with respect to the cradle 200 of the gun. A cam 212 having its end of bevelled shape followed by a portion having parallel sides, mounted on gun 1, comes, on every recoil movement of the gun, between rollers 210 and 211 so as to produce a displacement of roller 210 and therefore a pivoting of lever 208 having for its effect to compress spring 202.

It should be noted that, if no special precautions were taken a premature return of the gun toward the front would risk clearing the parallel sides of cam 212 from between rollers 210 and 211 and thus reducing the compression of spring 202 before said spring has transmitted energy to sliding member 143.

In order to avoid this risk, means are provided to act, on every recoil stroke of gun I, to lock lever 208 temporarily in its maximum rotation position (for which spring 202 is correctly stressed) as long as sliding member 143 has not been actuated.

' In the embodiment illustrated by the drawings such means include an arm- 208 of lever 208 which comes into a waiting position, when lever 208 has been given its maximum rotation, where it is maintained by a retractable holding finger 213 carried by cradle 200 and urged toward projecting position by a spring 214, said 3 waiting position of arm 208,, being shown in dotted lines in FIG. 1.

Holding finger 213 is provided with a lateral projection 213 disposed in such manner across the trajectory of sliding member 143 that the latter retracts said abutment 213, and releases lever 208-408,, when said sliding member 143 reaches the end of its active stroke and acts upon said projection 213 Concerning now the positive transmission mechanism to be interposed between breechblock 34 and the sliding member 143 of the feed mechanism it comprises a cam 75 located in the gun and journalled about an axis parallel to the longitudinal axis of said gun.

This cam 75 is given an oscillatory movement about its longitudinal axis by a driving finger 84 carried by breechblock 34 and engaged in a helical groove 83 provided in said cam 75.

On the other hand, cam 75 is positively connected with sliding member 143 through teeth 89 carried by a cam '75, which meshes with a toothed section 90 provided with external teeth 144 meshing with a pinion 215 rigid with a pinion 216 which in turn meshes with a rack 217 carried by sliding member 143.

In order to make the drawings easier to read, sliding member 143 and its control .pinion 216 have been shown as rotated through 90 toward the right in FIG. 2 with respect the positions they occupy in FIG. 1.

It will be understood that, owing to such a positive transmission mechanism interposed between breechblock 34 and the sliding member 143 of the feed mechanism, not only is said member 143 piloted accurately by said breechblock but the latter may, if necessary, for instance in case of an insufficient recoil of gun 1 with respect to its cradle 200, remedy to a temporary failure of the energy accumulator and then supply sliding member 143 with the energy necessary for ensuring the complete active stroke thereof. The return strokes of sliding member 143 require an amount of energy much smaller than the active strokes and they are controlled by breechblock 34 through the positive transmission mechanism above described.

The complete cycle of operation of the gun will now be described with reference to the diagram of FIG. 3 where the times t have been plotted in abscissas whereas the strokes of the movable elements are plotted in ordinates along axis L.

Curve C in solid lines illustrates the movement of gun 1 with respect to cradle 200 for a complete cycle of operation.

Curve C in dash-and-dot lines illustrates the movement of breechblock 34 during a complete cycle.

t shows the time of recoil of gun 1.

t shows the time for which the resilient energy accumulator 202 is placed under tension.

t represents the time for which said accumulator transmits energy to the reciprocating member 143 of the feed mechanism if the holding device is not used.

t represents the time of recoil for breechblock 34.

L represents the normal recoil of gun 1.

L represents the recoil stroke of the gun necessary for stressing accumulator 202.

It should be noted that the time for which the ac cumulator transmits energy to sliding member 143 is only a portion of the recoil time t; of the breechblock. As a matter of fact, it seems advantageous, in order to obtain a correct feed, to provide periods where the move: ment of sliding member 143 is neutralized, at the beginning and at the end of the recoil stroke of the breechblock, these neutralisation periods being obtained by giving the portions of the groove 83 of oscillating cam 75 that correspond to the beginning n and to the end 11 of the recoil stroke of said breechblock a rectilinear shape parallel to the generatrices of said oscillating cam.

The operation and the advantages of an automatic gun as above described result sufficiently clearly from the preceding description for making it unnecessary to give further explanations concerning them.

In a general manner, while the above description discloses what is deemed to be a practical and efiicient embodiment of the present invention, said invention is not limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principles of the invention as comprehended within the scope of the appended claims.

What is claimed is:

1. The combination of,

a stationary cradle,

a gun including a gun barrel longitudinally reciprocable with respect to said cradle,

a breechblock movable with respect to said gun barrel,

means carried by said cradle and operatively connected with said gun barrel for accumulating energy in response to each rearward displacement of said gun barrel with respect to said cradle,

a cartridge feed mechanism including a member movable with respect to said cradle,

transmitting means for transmitting the energy stored up in said energy accumulating means along an energy transmission path to said feed mechanism movable member, said energy transmission path bypassing the breechblock, and

positive piloting means between said breechblock and said feed mechanism movable member for controlling the instantaneous positions of said movable member with respect to said cradle in response to the movement of said breechblock with respect to said cradle.

2. A combination according to claim 1 wherein said breechblock is movable longitudinally with respect to said cradle and to said gun barrel and said positive piloting means include a cam journalled in said cradle about an axis parallel to the longitudinal axis of said gun barrel, said cam being provided with a curvilinear groove,

a driving finger carried by said breechblock and slidably engaged in said groove, and

pinion means interposed between said cam and said feed mechanism movable member for positively transmitting the rotary displacements of said cam to said feed mechanism movable member.

3. A gun according to claim 2 wherein the groove of said cam is provided, near its ends, with rectilinear portions parallel to the axis of said cam, said rectilinear portions being connected together by a portion of helical shape.

References Cited UNITED STATES PATENTS 1,293,021 2/1919 Browning 89-33 2,047,596 7/1936 Romberg 8933.25 2,644,365 7/1953 Maillard 8933.2 3,035,495 5/1962 Stoner 89-33.2 3,039,364 6/1962 Barr 8933.2 3,058,398 10/1962 Barr 89162 X 3,198,075 8/1965 Maillard 8933 FOREIGN PATENTS 323,401 7/ 1920 Germany.

SAMUEL FEINBERG, Primary Examiner, BENJAMIN A. BORCHELT, Examiner.

S. C. BENTLEY, Assistant Examiner. 

1. THE COMBINATION OF, A STATIONARY CRADLE, A GUN INCLUDING A GUN BARREL LONGITUDINALLY RECIPROCABLE WITH RESPECT TO SAID CRADLE, A BREECHBLOCK MOVABLE WITH RESPECT TO SAID GUN BARREL, MEANS CARRIED BY SAID CRADLE AND OPERATIVELY CONNECTED WITH SAID GUN BARREL FOR ACCUMULATING ENERGY IN RESPONSE TO EACH REARWARD DISPLACEMENT OF SAID GUN BARREL WITH RESPECT TO SAID CRADLE, A CARTRIDGE FEED MECHANISM INCLUDING A MEMBER MOVABLE WITH RESPECT TO SAID CRADLE, TRANSMITTING MEANS FOR TRANSMITTING THE ENERGY STORED UP IN SAID ENERGY ACCUMULATING MEANS ALONG AN ENERGY TRANSMISSION PATH TO SAID FEED MECHANISM MOVABLE MEMBER, SAID ENERGY TRANSMISSION PATH BYPASSING THE BREECHBLOCK, AND POSITIVE PILOTING MEANS BETWEEN SAID BREECHBLOCK AND SAID FEED MECHANISM MOVABLE MEMBER FOR CONTROLLING THE INSTANTANEOUS POSITIONS OF SAID MOVABLE MEMBER WITH RESPECT TO SAID CRADLE IN RESPONSE TO THE MOVEMENT OF SAID BREECHBLOCK WITH RESPECT TO SAID CRADLE. 